The present invention relates to an electron gun and a method for manufacturing the same, and more particularly, to a beading method for burying a plurality of electrodes in bead glasses and an electron gun manufactured by this method.
In general, an electron gun is composed of a plurality of electrodes. An inline-type electron gun has such a particular construction that a plurality of electrodes are buried and securely held in bead glasses in order to precisely manufacture an assembly of the red, green and blue electrodes in order.
Referring to FIG. 4, a beading apparatus for burying the plurality of electrodes in the bead glasses is so arranged that bead base 3 each including a stopper 2 for supporting the bead glass 1 are respectively fixed on the top ends of two arms 4, which two arms 4 are in turn arranged to be brought into an opening/closing movement by an arm driving means not shown while each of them are being swirled or moved in parallel relation with each other, or while they swirls and moves in parallel simultaneously. The beading apparatus also includes a heating means (not shown) for heating and softening the bead glasses 1 which are supported by the bead bases 3.
The bead glasses 1 are mounted on the bead bases 3, prior to being heated and softened at a temperature in the vicinity of a melting point of approximately 1200.degree. C. The bead glasses 1 are then pressed against the ends of the plurality of electrodes 6 assembled on a beading jig 5 so as to bury these ends of the electrodes thereinto. Succeedingly, the bead glasses are brought back into a condition that they are at a normal temperature, thereby completing fixture of the plurality of electrodes in the bead glasses.
The same kind of apparatus as the above is disclosed in Japanese Utility Model Laid-open Publication No. 52-42052.
In a certain conventional bead glass 1, there is provided a rectangular parallelepiped glass 10 as shown in FIG. 10A or a glass 11 of FIG. 11A having a convex portion 11a on the side which is not in contact with a G.sub.4 -electrode as shown in FIG. 11A. In a case of the glass 10 of FIG. 10A, a bead base 3 having a flat surface where the glass is mounted, is employed as shown in FIG. 10B. On the contrary, in a case of the glass 11 of FIG. 11A, a bead base 3 provided with a concave portion 3a for receiving the convex portion 11a of the glass 11 is employed as shown in FIG. 11B. When the glasses 10 of FIG. 10A are applied to a beading process as described in FIG. 4 by means of the bead bases 3 shown in FIG. 10B, an electron gun illustrated in FIG. 10C can be obtained. Similarly, the glasses 11 of FIG. 11A are applied to the beading process by means of the bead bases 3 shown in FIG. 11B in order to manufacture an electron gun illustrated in FIG. 11C.
Additionally, in FIGS. 10C and 11C, a reference numeral 20 designates a cathode body structure, and reference numerals 21 to 26 designate G.sub.1 -electrode, G.sub.2 -electrode, G.sub.3 -electrode, G.sub.4 -electrode, G.sub.5 -electrode and G.sub.6 -electrode, respectively.